This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The corpus luteum is a transient endocrine gland that forms from the remnants of the ruptured ovulatory follicle and is the primary source of progesterone, a hormone absolutely required to support pregnancy in all mammalian species. The lifespan of this gland can be divided into phases corresponding to its development (luteinization), maintenance, and regression (luteolysis). Proper development and maintenance of the corpus luteum is required for establishment and continuation of pregnancy if conception occurs. In the absence of fertilization, the corpus luteum regresses thus allowing for initiation of the next ovarian cycle. Pituitary-derived luteinizing hormone is the primary hormone responsible for corpus luteum development and maintenance in primates. While luteinizing hormone directly regulates many molecular and cellular processes that are critical for primate luteal development and function, its effects may also be mediated indirectly through local factors (e.g., paracrine or autocrine acting substances). The involvement and role of local factors in primate luteal activities, however, are poorly understood. From research utilizing rodents, domesticated animal species and primates, a significant role for arachidonate-derived prostaglandin species (i.e., PGE2 and PGF2alpha) in the regulation of luteal function has also been suggested. In the primate corpus luteum, however, the role(s) of prostaglandins remain poorly defined. Therefore, a genomic approach was utilized to determine if genes encoding proteins involved in prostaglandin synthesis, metabolism, and signaling are differentially or coordinately regulated in the corpus luteum through the menstrual cycle in rhesus macaques.